Aircraft typically include flaps attached to the wing fixed trailing edge which are movable between extended and retracted positions with respect to the fixed wing. Extension of the flaps increases the lift coefficient of the wing for the high lift, low speed flight phases (e.g. take-off and landing).
There are a wide variety of flap designs (e.g. single and multiple flap elements, slotted, unslotted etc.) and flap actuation mechanisms (e.g. drop hinge, flap track etc.) to achieve a similarly wide variety of extended flap configurations and motion paths. Generally, the flap extension path includes at least some aft movement and/or downward rotation of the flap element(s). The aft movement increases the wing chord, whilst the downward rotation increases the wing camber.
The flaps may be movable between a retracted position and one or more extended positions for low speed flight. During high speed flight phases it is also known to adjust the position of the flaps by small angles (+/−10 degrees, approx.) to vary the wing camber according to the cruising speed; so-called adaptive camber wings.
Depending on the flap geometry and desired motion path it is sometimes possible to house the flap actuation mechanism and the flap hinge wholly within the wing profile. However, it is common, particularly with more complex flap deployment geometry, to support the flap from the wing using a flap support structure. The flap support structure generally includes a flap support beam which houses at least a portion of the flap deployment mechanism for moving the flap, and has an outer aerodynamic fairing to reduce drag.
Existing flap support structures tend to be relatively complex and heavy, leading to an increase in manufacturing cost and assembly time, increased maintenance cost and time, and in-service fuel costs due to the weight penalty. They also tend to have a relatively large sectional area which impacts upon drag and hence in-service fuel costs.